Gerdau is one of the largest steelmakers in the world, and they’re using drones to take their work to the next level.
Headquartered in Sao Paulo, Gerdau employs over 30,000 people across 11 countries, and focuses on transforming iron ore and steel scrap into full-fledged steel products.
Gustavo Franca, IT Manager, and Rafael Alves, Mine Engineer, helped established an in-house drone program at Gerdau in Brazil as a proof of concept in early 2018, with an interest in how drone mapping can help them better capture and use topography data on their iron mines.
The project: Varzea do Lopes iron mine in Brazil
To start, the Gerdau team wanted to use drones to map Varzea do Lopes, an iron ore mine near the city of Belo Horizonte in Brazil. Varzea do Lopes produces over 6 million tonnes of iron ore every year, and supply it to a number of their steel plants across the country.
The need: safe, accurate drone surveying for mine planning
“Safety is our top priority,” Gustavo said. “We’re always looking for new tools and methods for improving safety on our projects.” Gerdau had a crew of six people at Varzea do Lopes that performed RTK surveys by foot: a time consuming workflow—especially given the size of the mine, the pit alone covering more than 250 acres—that took between 24-48 hours to collect and process data into final deliverables. They were looking to keep their team out of harm’s way and improve their survey productivity.
The Gerdau team was also looking for a tool to create accurate, precise point clouds that they could bring into HxGN MinePlan 3D, their mine planning software from Hexagon Mining. This would help with blast planning, measuring stockpiles, documenting the mine at key stages, and with longer term projects such as design and expansions. “It was important that we have the capability to export drone data into other tools, such as MinePlan 3D, to calculate and compare volumes and measurements,” Gustavo said.
As Gerdau started to build their in-house drone program, they had a few key decision criteria for their drone software of choice, including:
1. Easy to fly and share data
2. Best-in-class vertical and horizontal accuracy, within 1.5% accuracy of laser scanning
3. File formats that can be used in MinePlan 3D and by the rest of the Gerdau team
The solution: 3DR Site Scan with the DJI Phantom 4 Pro
“We recognized several opportunities to use drones on our mines,” Gustavo said, “and we decided to work with 3DR and use Site Scan.”
They set over 40 ground control points across different parts of the mine and have been regularly surveying using Site Scan and a DJI Phantom 4 Pro drone. They’re performing volume measurements directly in Site Scan, comparing orthomosaics to track progress over time, and sharing rich maps and 3D models with the rest of the company.
They’re making the data accessible to other parts of Gerdau, such as the geology team. “Our geologists are using georeferenced maps and point clouds to understand the different types of rocks on-site,” Rafael said. “It makes their life easier: now they don’t have to go to the mine every time they need data. They can just view the latest flight data online to get the answers they need.”
Bringing the data into MinePlan 3D
Once they have an up-to-date point cloud of their site, the Gerdau team will export an LAS file from Site Scan and bring it into MinePlan 3D for measurements and planning. “We use our point clouds in MinePlan 3D to draw mine plans, which helps us decide how much we actually need to mine,” Rafael continues. “The workflow is easy: we just import the point cloud, generate the surface, and use the point cloud mesher feature in MinePlan 3D to do our work. We then make the plan and share it with our operations crew each month so they can execute it. We need accurate topography data to do this well, and that’s where Site Scan comes in.”
"The workflow is easy: we just import the point cloud, generate the surface, and use the point cloud mesher feature in MinePlan 3D to do our work."Rafael AlvesMine Engineer
1. Improved safety and survey productivity
By flying regularly and mapping the mine with Site Scan, Gerdau is making their topographic survey workflow far safer and significantly more efficient compared to conventional methods and laser scanning:
“We’re protecting our team with this workflow,” Gustavo explains. “It brings a safety benefit that’s very important to us.”
Their drone program also makes it possible to perform surveys and inspections more frequently: “In the past, I could inspect my operation once a week,” Gustavo said. “Now, I can inspect it every day if necessary, because it’s so easy to do so. By building this drone program in Gerdau, we’re transforming our current process and creating new ones.”
"In the past, I could inspect my operation once per week. Now, I can inspect it every day."Gustavo FrancaIT Manager
2. Accurate data
With volume measurements being such an important part of their day-to-day work, Gerdau wanted to ensure that their drone data was just as accurate as RTK GPS and laser scanning. To compare accuracy, they performed a test survey of a stockpile with three different methods: conventional RTK GPS, laser scanning, and drone capture with Site Scan. Using laser scan data as the baseline, they found that the volume measurements from Site Scan had only a 1.16% difference from the laser scan data, and they were more accurate than the topography data captured with RTK GPS.
"Volume measurements from Site Scan had only a 1.16% difference from laser scan data, and they were more accurate than topography data captured with RTK GPS."
When comparing cross-sections of a mine wall between Site Scan data and conventional RTK data, they found that the profile lines were nearly the exact same:
3. $100,000+ annual savings
By reducing the need to capture topography data with RTK GPS, Gerdau’s drone program has saved over $26,000 USD (R$110,000 Brazilian Real) in 2018 alone (including the cost of the drone and Site Scan software). As they continue to standardize on Site Scan across projects and use it throughout the full year, they’re on track to earn a return on investment of approximately $107,000 USD (R$430,000 Brazilian Real) in 2019.
Now that Gerdau has found initial success with their drone program on the Varzea do Lopes iron mine, they’re looking to scale drone operations to more projects throughout the company. As Rafael said: “Any part of our business that relies on topography data should be using a drone and Site Scan.”
For example, in addition to their mining operations, Gerdau is now starting to use drones at their steel processing plants in Brazil, using high-resolution orthomosaics to better track and manage their inventory.
“We want to continue expanding our use of Site Scan because of its ease of use, user experience, and central management of data. In the future, we’ll be managing a fleet of drones in this platform, and get valuable insights about our operations every day.”